Apparatus for conserving low bciling hydrocarbon vapors of centrifuged oil



Sept. 12, 1939. H. o. LlNDGREN 2,172,513

APPARATUS FOR CONSERVING LOW BOILING HYDROCARBON VAPORS OF CENTRIFUGEDOIL Filed March 12, 1938 H4728- fkdyff z Patented Sept. 12, 1939APPARATUS FOR r 2 T" omes CONSERVING LOW BOIL- "'ING nYDRooAnBoN veronsor CENTRI:

. FUGED OIL Hans Olof Lindgren, Appelviken, Sweden, as-

signor to The De Laval Separator Company, New York, N. Y., a corporationof New Jersey Application March 12, 1938, Serial No. 195,663 In SwedenMarch 24, 1937 1 Claim.

In the production of benzine and similar low boiling but normally liquidhydrocarbons, the latter usually are subjected to refining with concentrated sulphuric acid. This is now often effected by mixing, forexample, the crude benzine with concentrated sulphuric acid in asuitable apparatus permitting of continuous operation and bysubsequently separating the mixture in a centrifugal separator; refinedbenzine and socalled sludge thereby being obtained. Often it cannot beavoided that the temperature of the mixture during separation isrelatively high and higher than the boiling point of some of theconstituents of the benzine. Vapor is thereby easily formed in thebenzine, especially during the strong mechanical action to which theliquid is subjected when it is thrown out of. the separator bowl intothe collecting vessel. It has not been possible to prevent part of thefumes from penetrating down to the oil bath of the separator, whichentails a dilution and deterioration of the lubricating oil. The fumesalso sometimes escape to the room in which the separator is erected,which causes discomfort for the operators.

According to the present invention these inconveniences are avoided bymaking the chamher which surrounds the centrifugal bowl and into whichthe liquid is thrown when it leaves the bowl gas-tight from theatmosphere, and by connecting it through a. gas pipe with theventilation system which is normally arranged in an oil refinery. Thisventilation system, by which all those tanks in the refinery communicatein which hydrocarbon fumes may be evolved, com municates with theatmosphere only through an installation for the recovery of thehydrocarbons in liquid form, for instance, by means of active carbon. Ifan evolution of gases takes place in the separator with thisarrangement, the gases cannot escape directly to the air, but are forcedto pass through the recovering installation, any losses thereby beingavoided.

A separator of. the present type substantially consists of a chamberenclosing the driving mechanism of the machine and another chamber forthe separator bowl, the latter chamber communicating with the collectingvessels into which the liquid is thrown when it leaves the bowl. Byproviding a packing device between the chamber enclosing the drivingmechanism and the chamber in which the bowl is arranged, it is possibleto prevent any fumes from penetrating into the chamber for the drivingmechanism and contaminating the lubricating oil. The provision of apacking in this place, however, presents certain difliculties, because atight joint must be established around the rapidly rotating spindlewhich carries and drives the bowl. On the other hand, it is possible toestablish a reliable tightening of means of, for instance, a liquid sealaround the spindle or a labyrinth packing. There is, however, nothingthat prevents the chamber for the driving mechanism, an oil bath forwhich such chamber usually contains, from being made a part of the spaceseparated from the atmosphere but communicating with the ventilationsystem. It is thereby not possible to prevent a condensation ofhydrocarbons in the lubricating oil, but this objection may be avoidedby either changing the oil at suitable intervals or by driving 01f thehydrocarbons condensed in the oil continuously by means of a specialarrangement.

It is often advantageous to arrange a container comprising severalcompartments and provided with inspection glasses, test cocks, etc. inthe neighborhood of the separator, to which compartments refinedbenzine, goudron, excess liquid, etc. are conducted and whichcommunicate with each other at the upper part through the ventilationchannel. The conduit through which, as stated before, the separatorcommunicates with the ventilation system of the refinery is then coupledto the said container, the gas space of which in turn communicates withthat of the separator, either through a special ventilation pipe orthrough the discharge pipes for liquid, the diameter of which is thensufficiently large to insure that they will not fill with liquid.

The accompanying drawing is a side elevation, largely diagrammatic, ofan installation of one embodiment of the invention. In the figure, l isthe separator frame, in the lower chamber 2 of which the drivingmechanism 3 is located, and in the upper chamber 20 of which theseparator bowl 4 is arranged. The latter is surrounded by the collectingvessels 5, 6 and l' which are hermetically separated from theatmosphere. For this purpose, among other things, a packing device isarranged at the spindle bearing 8 or in the place 3 where the horizontaldriving shaft extends through the frame. The different collectingvessels communicate by pipes with the container H). The variouscollecting compartments l2, l3, M and i5, which are provided withinspection glasses H, communicate at the upper part with each other, andthe container communicates by pipe It with the ventilation system I! ofthe refinery, which communicates with the air through the arrangement l8for the recovering of the hydrocarbons. l9 represents a tank containingthe liquid mixture to be subjected to the centrifugal separator. Thissupply tank is connected through a feed pipe 2! and feed pump 22 to thecentrifugal separator. The tank [9 is shown as also communicating withthe pipe l6 so that any vapor forming in the mixture beforecentrifugation will also escape into the ventilating pipe I'I.

What I claim and desire to protect by Letters Patent is:

The combination with a centrifugal separator for refining low boilingliquid hydrocarbons and collecting vessels surrounding the separator andclosed to the atmosphere and adapted to receive the separatedconstituents and each provided with a single fluid outlet, of a recoverysystem for condensing condensable hydrocarbon vapors, receivers for theseparated liquids, closed fluid passages between the respective outletsfrom the collecting vessels and the respective receivers for conveyingto the latter both separated liquid constituents and vapors, and aclosed vapor passage connecting the vapor spaces of the receivers 10with the recovery system.

HANS OLOF LINDGREN.

